733
FXUS63 KUNR 291036
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
436 AM MDT Wed May 29 2024

.KEY MESSAGES...

-Thunderstorms this afternoon and evening with potential for hail
 and damaging wind

-Chance of showers/thunderstorms continue through early next week.

&&

.DISCUSSION...(Today Through Tuesday)
Issued at 201 AM MDT Wed May 29 2024

Current surface map places remnants of back door front across
central Montana into eastern Wyoming. Clear skies across the
forecast area with a some locally gusty south winds. Upper trough
over the Pacific Northwest slides across the Rockies today. Gusty
south winds spread across the forecast area this morning with
pressure falls/tight pressure gradient. Strongest winds will be on
the plains north and east of the Black Hills. HREF probability of
wind gusts >45mph is at 10% or less, so will not issue any wind
headlines at this time. Surface trof remains over eastern Wyoming
through this afternoon, then shifts eastward through western South
Dakota in response to the shortwave ejecting from upper trough.
Buoyancy increases this afternoon with low level moisture
transport and steep mid level lapse rates resulting in MLCAPE of
1500-2000J/KG across far western South Dakota. Early afternoon
thunderstorm development is expected across the higher elevations
of eastern Wyoming and the northern Black Hills with additional
development along the surface trof. Storms will eventually
organize in a broken line along the surface trough with increased
forcing. Shear is on the weaker side, but an uptick in shear is
expected this evening as mid level winds increase. Combination of
buoyancy/shear will sufficient for strong/severe storms this
afternoon and evening. Cold front pushes through overnight with a
brief period of gusty northwest winds. Cooler on Thursday with a
few lingering showers/thunderstorms possible over the Black Hills
and south central South Dakota.

Active pattern continues through the weekend into early next week
with wave train embedded in quasi-zonal flow. This will result in
a daily chance of showers and thunderstorms. Above average
temperatures are expected for the weekend into early next week.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Thursday Morning)
Issued At 430 AM MDT Wed May 29 2024

VFR conditions will continue for most areas through the forecast
period. South to southeasterly winds will increase this morning,
sustained 15 to 25 kts with gusts up to 35 kts at times. There is
the potential for scattered TSRA to develop from west to east
across the region through this afternoon (after around 18z) -
these TS may impact the KGCC and KRAP terminals. Due to low
confidence in timing and location of storms, have opted to leave
mention out of the KRAP and KGCC TAFs for now. Locally MVFR/IFR
conditions with gusty, erratic winds and hail may be encountered
in and around any storms.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...7
AVIATION...Wong